Hot gas electrofilter



Jan. 19, 1965 F. KAPPls ETAL Hor GAS ELECTROFILTER 4 Sheets-Sheet l Filed Oct. 28, 1960 EN w FrlEJrI i rmlve vr Jam 19, 1965 F. KAPPls ETAL. 3,166,389

HOT GAS ELECTROFILTER med oct. 28. 1960v 4 sheets-sheet 2v *l ,ifm Ffga k-JDM Jan. 19, 1965 Filed Oct. 28. 1960 F. KAPPIS ETAL HOT GAS ELECTROFILTER 4 Sheets-Sheet 5 INVENTORS rx/Eo/cf/ KiP/ms,

BY 2 Wr/a? ATTORNEYS Jan. 19, 1965 F. KAPPls ETAL 3,166,389

HOT GAs ELBCTROFILTER Filed Oct. 28. 1960 4 Sheets-Sheet 4 Agg j L Fly. 5

31mg/ Wtntr K/v. Mnuun mun United States Patent Office 3,166,389 Patented Jan. 19, 1965 The invention relates t-o electrolters, and particularf work or concrete. These housings consist of walls and a cover of a thickness of at least 'to 40 cm. and'more. Inl the conventional concrete structures, changes in the crosssectional form of the supports and beams connected with the stationary wall, which may be for example be cast integral with the wall, are common, because the loads on the interior filter elements such as the discharge spaces, the precipitating electrodes or the insulators as well as the exterior filter elements such as stabilizers must be transmitted through them to the base or foundation. t

A certain thickness is also required for the purpose of heat insulation. For the purpose of cleaning hot acid gases, it has been found that the electrolter housing formed of reinforced concrete of ordinary construction has substantial disadvantages. Because of the great temperature differences between the temperatures inside and outside the electroiilter housing there arise in the thick concrete walls strong temperature differences, which lead to changes in dimensions and to mechanical stresses in the concrete, so that often cracks arise and the walls are not gas-tight. Because of the varying cross-sections p which are absolutely necessary for the purpose of mechanical stability, there arise, with constant temperatures inside the electrolter housing, vari-able temperatures` on the outer walls which can lead to uncontrolled ratios of stress in the construction and often to the formation of cracks.

The present invention has the purpose of 4providing a construction which overcomes these disadvantages of the prior art devices. i

A primary object of the invention is to decrease to a minimum or to prevent altogether'harmful temperature differences in the housing walls.

Another object of the invention is` to provide an arrangement in which the mechanical stresses which exist inside the concrete walls can be easily controlled.

According to the invention, thisproblem is solved by constructing the complete electrolter of two structural parts electrically insulated from each other, the lter housing being for example of structural cement and as thin walled as possible and therefore not necessarilyV self-supporting (hereinafter referred to as the Warm construction) and being provided with heat insulation and the second part consisting of a frame of reinforced concrete or the like (hereinafter referred to as cold construction) in which the filter housing is freely movable, by hanging or by being otherwise supported in the frame. In this Way the weight of the lter housing as well as the discharge and precipitating electrodes arranged therein are transmitted to the cold frame structure, for which purpose the mounting and supporting insulators are mounted between a double truss of the frame. Because of the thin walls which are possible with this construction (their thickness when formed of concrete lies in practical applications for example between 10 and 20 cm.), the electroiilter housing which either hangs free in the reinforced concrete frame or slides on guides or rollers, and which additionally is heat insulated, can be subjected to no high harmful temperature differentials in the concrete walls and especially to no such temperature differences in the frame construe tion which is insulated from the housing. An insignificant temperature expansion in the walls of the Warm construction cannot lead to destruction of the walls or to the formation of cracks, because the warm construction itself can expand as desired, since according to another t feature of the invention it is not rigidly connected with the cold construction or with the foundation, but throughl expansion or sliding means for example slide guides or the like it is arranged freely movable in the frames. v

The electrolter housing is, according to the 'invention, so constructed that the temperature drop inside the reinforced concrete walls and cover of the warm construction does not exceed 20 C. The dust hoppers are, if desired, supported from the electrolter through expansion joints. For protection against the weather the whole outer surfaces can for example be coated with known insulating material. In order to take up smoothly the expansions and occasional movements (for example from wind pressure) of the warm construction in the frames, the elcctrolter housing (warm construction) is supported by 'springs with respect to the reinforced concrete frames (cold construction). It lies within the scope of the invention to use, instead of the reinforced concrete cold frame construction, an iron construction, in which the reinforced concrete electrolter housing of the previously described light construction hangs or is supported. It is also possible within the invention to make the warm construction of some other material than reinforced concrete, such'as synthetic resin or metal, for example, light metals suitably insulated from the cold frame construction. v

The advantage of the construction according to the invention consists in the fact that the electrolter housing, in contrast to conventional ones, has especially high elasticity, so that no cracks in the walls can arise as a consequence of changes in dimensions or as a consequence of too great temperature differences between the inside of the housing and its surroundings, so that drawing in of false air is not necessary and the essential supporting construction is not warmed, but remains practically at the same temperature as its surroundings. In this way it is possible to work at considerably higher temperatures than heretofore. Tests have shown that -the maximum temperature lies at l250 to 00"V C. Also concrete, a high saving in material, as much as 25%, as Y compared to conventional concrete electrolters is possible.

Further objects and advantages of the invention will appear more fully from the following description especially when taken in conjunction with the accompanying drawings, which form a part thereof.

FIG. 1 shows in side elevation a filter embodying the invention;

FIG. 2 is across-section through the electroiilter of FIG. 1; Y

FIG. 2a is a cross-section showing the mounting of the precipitating electrodes;

FIG. 3 is a cross-section through another form of electrolter;

FIG. 4 is `a side elevation of another modification;

FIG. 5 is a cross-section through the electrofilter of FIG. 4; and

FIG. 6 is a cross-section through a further modification.

In the drawings, with reference to FIGS. 1 and 2, the

sulating layer 4, for example, of fibre sheets bonded Y with cement. Y

In the form of the invention shown in FIGS. 1, 2 and 3i, the electrofilter housing is hung on hangers 10 in the frames 2, being suspended from the webs 12 ofthe frame. Steel springs 5 are provided between the side walls of the electrolter housing and the uprights of theframes in `order to prevent contact therebetween and to damp any movement of the electrolter housing.

The discharge electrodes 9 are carried by high tension insulators 11 through hangers 17, which pass free` ly but gas-tightly through the lid of the housing. The precipitating electrodes 9', as shown in FIG. 2a, are

carried, in a similarmannefr from the frame by hangers 17,vbut without the interposition of insulators.

The supply of high tension current can take Vplace through thev insulators 11, whichv are constructed as lead-through insulators.

The dust bins '7 are, in the form of FIGS.'1 and 2, directly connected with the electroilter housing. In the form of FIG. 3, the hoppers 13 are connected with fthe electroilter housing gas-tightly by expansion joints 14. The reinforced concrete frame constructions 2 are secured on a base 15,.which may be below or partly above the earth.

In the form ,of FIG. 3, the hopper 13 is so constructed that it rests with its lower part on a slide 16 which may be providedwith a lubricating medium.

In the form of FIGS. 4 and 5, as well as inwthat of FIG. 6, the filter housing rests on guides 6 carried by brackets 8, these guidesv being formed of lubricating material.

arenas@ The guides 6 are also of an insulating material as are the brackets 8.

While we have described herein some embodiments of our invention, we wish it to be understood that We do not intend to limit ourselves thereby except within the scope of the claims hereto or hereinafter appended.

l. A hot gas ele'ctrolilter comprising a reinforced concrete frame, afilter-housing of reinforced concrete of a thickness of not over 20 cm. withinithe frame,ldischarge :and precipitating electrodes within s aid iilter housing,

v means directly supporting said discharge electrodes from said frame independently ofthe. lter-housing and electrically insulating said discharge' electrodes from said frame, means directly supporting the precipitating electrodes from said frame independently of the filter-housing, a layer of'insulation aroundthe outsideof said housing, and means resiliently mounting said filter-housing in the frame, whereby the temperature drop in the walls of the filter-housing does not exceed 20 C.

2. An electrolter housing as claimed in claim 1, having a dust hopper, tand expansion joints connecting the dust hopper with the iilter housing.

References Cited in the tile of this patent Germany July 8, 

1. A HOT GAS ELECTROFILTER COMPRISING A REINFORCED CONCRETE FRAME, A FILTER-HOUSING OF REINFORCED CONCRETE OF A THICKNESS OF NOT OVER 20 CM. WITHIN THE FRAME, DISCHARGE AND PRECIPITATING ELECTRODES WITHIN SAID FILTER HOUSING, MEANS DIRECTLY SUPPORTING SAID DISCHARGE ELECTRODES FROM SAID FRAME INDEPENDENTLY OF THE FILTER-HOUSING AND ELECTRICALLY INSULATING SAID DISCHARGE ELECTRODES FROM SAID FRAME, MEANS DIRECTLY SUPPORTING THE PRECIPIATING ELECTRODES FROM SAID FRAME INDEPENDENTLY OF THE FILTER-HOUSING A LAYER OF INSULATION AROUND THE OUTSIDE OF SAID HOUSING AND MEANS RESILIENTLY MOUNTING SAID FILTER-HOUSING IN THE FRAME, WHEREBY THE TEMPERATURE DROP IN THE WALLS OF THE FILTER-HOUSING DOES NOT EXCEED 20*C. 